docstr: Raise an error when a key has not been given
          
docstr_tok: ["Raise","an","error","when","a","key","has","not","been","given"]
code: def test_key_none(self):
      """Raise an error when a key has not been given"""
      try:
          AlphaVantage()
          self.fail(msg="A None api key must raise an error")
      except ValueError:
          self.assertTrue(True)
  
imports: from ..alpha_vantage.alphavantage import AlphaVantage
  from ..alpha_vantage.timeseries import TimeSeries
  from ..alpha_vantage.techindicators import TechIndicators
  from ..alpha_vantage.sectorperformance import SectorPerformances
  from ..alpha_vantage.foreignexchange import ForeignExchange
  from ..alpha_vantage.fundamentaldata import FundamentalData
  from pandas import DataFrame, Timestamp
  import unittest
  import sys
  import collections
  from os import path
  import requests_mock
label_desc: Use image node_id 2 for calling the TestAlphaVantage obj's underlying member method code with example usage: obj.test_key_none() without return types